feat(vertex): add support for US multi-region endpoint

Author: TomerAberbach

vertex/vertex.go

@@ -46,9 +46,12 @@ func WithCredentials(ctx context.Context, region string, projectID string, creds
 	middleware := vertexMiddleware(region, projectID)
 
 	var baseURL string
-	if region == "global" {
+	switch region {
+	case "global":
 		baseURL = "https://aiplatform.googleapis.com/"
-	} else {
+	case "us":
+		baseURL = "https://aiplatform.us.rep.googleapis.com/"
+	default:
 		baseURL = fmt.Sprintf("https://%s-aiplatform.googleapis.com/", region)
 	}
 

vertex/vertex_test.go

@@ -0,0 +1,58 @@
+package vertex
+
+import (
+	"context"
+	"testing"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+
+	"github.com/anthropics/anthropic-sdk-go/internal/requestconfig"
+)
+
+func TestBaseURLForRegion(t *testing.T) {
+	testCases := []struct {
+		name        string
+		region      string
+		expectedURL string
+	}{
+		{
+			name:        "global region",
+			region:      "global",
+			expectedURL: "https://aiplatform.googleapis.com/",
+		},
+		{
+			name:        "us region",
+			region:      "us",
+			expectedURL: "https://aiplatform.us.rep.googleapis.com/",
+		},
+		{
+			name:        "specific region",
+			region:      "us-central1",
+			expectedURL: "https://us-central1-aiplatform.googleapis.com/",
+		},
+		{
+			name:        "europe region",
+			region:      "europe-west1",
+			expectedURL: "https://europe-west1-aiplatform.googleapis.com/",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			creds := &google.Credentials{
+				TokenSource: oauth2.StaticTokenSource(&oauth2.Token{AccessToken: "fake"}),
+			}
+			opt := WithCredentials(context.Background(), tc.region, "test-project", creds)
+
+			cfg := &requestconfig.RequestConfig{}
+			if err := opt.Apply(cfg); err != nil {
+				t.Fatalf("Failed to apply option: %v", err)
+			}
+
+			if cfg.BaseURL.String() != tc.expectedURL {
+				t.Errorf("Expected base URL %q, got %q", tc.expectedURL, cfg.BaseURL.String())
+			}
+		})
+	}
+}